On 10/31/23 08:49, David Ober wrote:
This addition adds in the ability for the system to scan the
MEC172x EC chip in Lenovo ThinkStation systems to get the
current fan RPM speeds and the Maximum speed value for each
fan also provides the current CPU and DIMM thermal status
Signed-off-by: David Ober <dober6023@xxxxxxxxx>
v2 fixed mixcased naming
v2 add mutex protection
v2 removed references to ACPI as it is not used
v2 added comment to explain why returning a -1 is needed
---
drivers/hwmon/Kconfig | 10 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/lenovo-ec-sensors.c | 484 ++++++++++++++++++++++++++++++
3 files changed, 495 insertions(+)
create mode 100644 drivers/hwmon/lenovo-ec-sensors.c
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index ec38c8892158..821741ec0d2f 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -862,6 +862,16 @@ config SENSORS_LAN966X
This driver can also be built as a module. If so, the module
will be called lan966x-hwmon.
+config SENSORS_LENOVO_EC
+ tristate "Microchip MEC172X Chip for Lenovo ThinkStation"
+ depends on I2C
+ help
+ If you say yes here you get support for LENOVO
+ EC Sensors on newer ThinkStation systems
+
+ This driver can also be built as a module. If so, the module
+ will be called lenovo_ec_sensors.
+
config SENSORS_LINEAGE
tristate "Lineage Compact Power Line Power Entry Module"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 4ac9452b5430..aa3c2dc390ec 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -104,6 +104,7 @@ obj-$(CONFIG_SENSORS_JC42) += jc42.o
obj-$(CONFIG_SENSORS_K8TEMP) += k8temp.o
obj-$(CONFIG_SENSORS_K10TEMP) += k10temp.o
obj-$(CONFIG_SENSORS_LAN966X) += lan966x-hwmon.o
+obj-$(CONFIG_SENSORS_LENOVO_EC) += lenovo-ec-sensors.o
obj-$(CONFIG_SENSORS_LINEAGE) += lineage-pem.o
obj-$(CONFIG_SENSORS_LOCHNAGAR) += lochnagar-hwmon.o
obj-$(CONFIG_SENSORS_LM63) += lm63.o
diff --git a/drivers/hwmon/lenovo-ec-sensors.c b/drivers/hwmon/lenovo-ec-sensors.c
new file mode 100644
index 000000000000..e2b14b3aea08
--- /dev/null
+++ b/drivers/hwmon/lenovo-ec-sensors.c
@@ -0,0 +1,484 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * HWMON driver for MEC172x chip that publishes some sensor values
+ * via the embedded controller registers specific to Lenovo Systems.
+ *
+ * Copyright (C) 2023 David Ober (Lenovo) <dober@xxxxxxxxxx>
+ *
+ * EC provides:
+ * - CPU temperature
+ * - DIMM temperature
+ * - Chassis zone temperatures
+ * - CPU fan RPM
+ * - DIMM fan RPM
+ * - Chassis fans RPM
+ */
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/hwmon.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/units.h>
+
+#define MCHP_SING_IDX 0x0000
+#define MCHP_EMI0_APPLICATION_ID 0x090C
+#define MCHP_EMI0_EC_ADDRESS_LSB 0x0902
+#define MCHP_EMI0_EC_ADDRESS_MSB 0x0903
+#define MCHP_EMI0_EC_DATA_BYTE0 0x0904
+#define MCHP_EMI0_EC_DATA_BYTE1 0x0905
+#define MCHP_EMI0_EC_DATA_BYTE2 0x0906
+#define MCHP_EMI0_EC_DATA_BYTE3 0x0907
+
+#define io_write8(a, b) outb_p(b, a)
+#define io_read8(a) inb_p(a)
+
+static inline uint8_t
+get_ec_reg(unsigned char page, unsigned char index)
+{
+ u8 onebyte;
+ unsigned short m_index;
+ unsigned short phy_index = page * 256 + index;
+
+ if (io_read8(MCHP_EMI0_APPLICATION_ID) != 0) /* EMI access locked */
+ return -1;
+
Whatever the explanation is, returning -1 from a function declared as
returning uint8_t doesn't make sense. Not checking the return
code in the calling function makes even less sense.
+ io_write8(MCHP_EMI0_APPLICATION_ID, 0x01);
+
+ m_index = phy_index & 0x7FFC;
+ io_write8(MCHP_EMI0_EC_ADDRESS_LSB, m_index);
+ io_write8(MCHP_EMI0_EC_ADDRESS_MSB, m_index >> 8);
+
+ switch (phy_index & 0x0003) {
+ case 0:
+ onebyte = io_read8(MCHP_EMI0_EC_DATA_BYTE0);
+ break;
+ case 1:
+ onebyte = io_read8(MCHP_EMI0_EC_DATA_BYTE1);
+ break;
+ case 2:
+ onebyte = io_read8(MCHP_EMI0_EC_DATA_BYTE2);
+ break;
+ case 3:
+ onebyte = io_read8(MCHP_EMI0_EC_DATA_BYTE3);
+ break;
+ }
+
+ io_write8(MCHP_EMI0_APPLICATION_ID, 0x01); /* write same data to clean */
+ return onebyte;
+}
+
+static const char * const systems[] = {
+ "Tomcat",
+ "Hornet",
+ "Falcon",
+ "Manta_",
+};
+
+static const char * const lenovo_px_ec_temp_label[] = {
+ "CPU1",
+ "CPU2",
+ "R_DIMM1",
+ "L_DIMM1",
+ "R_DIMM2",
+ "L_DIMM2",
+ "PCH",
+ "M2_R",
+ "M2_Z1R",
+ "M2_Z2R",
+ "PCI_Z1",
+ "PCI_Z2",
+ "PCI_Z3",
+ "PCI_Z4",
+ "AMB",
+};
+
+static const char * const lenovo_gen_ec_temp_label[] = {
+ "CPU1",
+ "",
+ "R_DIMM",
+ "L_DIMM",
+ "",
+ "",
+ "PCH",
+ "M2_R",
+ "M2_Z1R",
+ "M2_Z2R",
+ "PCI_Z1",
+ "PCI_Z2",
+ "PCI_Z3",
+ "PCI_Z4",
+ "AMB",
+};
+
+static const char * const px_ec_fan_label[] = {
+ "CPU1_Fan",
+ "CPU2_Fan",
+ "Front_Fan1-1",
+ "Front_Fan1-2",
+ "Front_Fan2",
+ "Front_Fan3",
+ "MEM_Fan1",
+ "MEM_Fan2",
+ "Rear_Fan1",
+ "Rear_Fan2",
+ "Flex_Bay_Fan1",
+ "Flex_Bay_Fan2",
+ "Flex_Bay_Fan2",
+ "PSU_HDD_Fan",
+ "PSU1_Fan",
+ "PSU2_Fan",
+};
+
+static const char * const p7_ec_fan_label[] = {
+ "CPU1_Fan",
+ "",
+ "HP_CPU_Fan1",
+ "HP_CPU_Fan2",
+ "PCIE1_4_Fan",
+ "PCIE5_7_Fan",
+ "MEM_Fan1",
+ "MEM_Fan2",
+ "Rear_Fan1",
+ "",
+ "BCB_Fan",
+ "Flex_Bay_Fan",
+ "",
+ "",
+ "PSU_Fan",
+ "",
+};
+
+static const char * const p5_ec_fan_label[] = {
+ "CPU_Fan",
+ "",
+ "",
+ "",
+ "",
+ "HDD_Fan",
+ "Duct_Fan1",
+ "MEM_Fan",
+ "Rear_Fan",
+ "",
+ "Front_Fan",
+ "Flex_Bay_Fan",
+ "",
+ "",
+ "PSU_Fan",
+ "",
+};
+
+static const char * const p7_amd_ec_fan_label[] = {
+ "CPU1_Fan",
+ "CPU2_Fan",
+ "HP_CPU_Fan1",
+ "HP_CPU_Fan2",
+ "PCIE1_4_Fan",
+ "PCIE5_7_Fan",
+ "DIMM1_Fan1",
+ "DIMM1_Fan2",
+ "DIMM2_Fan1",
+ "DIMM2_Fan2",
+ "Rear_Fan",
+ "HDD_Bay_Fan",
+ "Flex_Bay_Fan",
+ "",
+ "PSU_Fan",
+ "",
+};
+
+struct ec_sensors_data {
+ struct mutex mec_mutex; /* lock for sensors write */
+ u8 platform_id;
+ const char *const *fan_labels;
+ const char *const *temp_labels;
+};
+
+static int
+lenovo_ec_do_read_temp(struct ec_sensors_data *data, u32 attr, int channel, long *val)
+{
+ u8 LSB;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ mutex_lock(&data->mec_mutex);
+ LSB = get_ec_reg(2, 0x81 + channel);
+ mutex_unlock(&data->mec_mutex);
+ if (LSB > 0x40) {
+ *val = (LSB - 0x40) * 1000;
+ } else {
+ *val = 0;
+ return -1;
No. Return valid Linux error codes. Also, error handling
should come first, and writing 0 into *val when returning
an error is useless.
Also, get_ec_reg() returns 0xff if "EMI access locked",
which is treated as valid here (and elsewhere). This doesn't
make sense to me.
+ }
+ return 0;
+ default:
+ break;
+ }
+ return -EOPNOTSUPP;
+}
+
+static int
+lenovo_ec_do_read_fan(struct ec_sensors_data *data, u32 attr, int channel, long *val)
+{
+ u8 LSB, MSB;
+
+ channel *= 2;
+ switch (attr) {
+ case hwmon_fan_input:
+ mutex_lock(&data->mec_mutex);
+ LSB = get_ec_reg(4, 0x60 + channel);
+ MSB = get_ec_reg(4, 0x61 + channel);
+ mutex_unlock(&data->mec_mutex);
+ if ((MSB << 8) + LSB != 0) {
This is confusing. Why not just "if (MSB || LSB)" ?
+ mutex_lock(&data->mec_mutex);
+ LSB = get_ec_reg(4, 0x20 + channel);
+ MSB = get_ec_reg(4, 0x21 + channel);
+ mutex_unlock(&data->mec_mutex);
+ *val = (MSB << 8) + LSB;
+ return 0;
+ }
+ return -1; /* Returning -1 here has the sensors tool mark the FAN speed as N/A */
-1 translates to -EPERM. No, this is unacceptable.
Please return valid Linux error codes. If you _really_ think
that this should return -EPERM, explain in detail (and use -EPERM).
FWIW, there is -ENODATA which is displayed in the "sensors"
command as N/A. Maybe that is what you want.
+ case hwmon_fan_max:
+ mutex_lock(&data->mec_mutex);
+ LSB = get_ec_reg(4, 0x60 + channel);
+ MSB = get_ec_reg(4, 0x61 + channel);
+ mutex_unlock(&data->mec_mutex);
+ if ((MSB << 8) + LSB != 0) {
+ mutex_lock(&data->mec_mutex);
+ LSB = get_ec_reg(4, 0x40 + channel);
+ MSB = get_ec_reg(4, 0x41 + channel);
+ mutex_unlock(&data->mec_mutex);
+ *val = (MSB << 8) + LSB;
+ } else {
+ *val = 0;
+ }
+ return 0;
+ case hwmon_fan_min:
+ case hwmon_fan_div:
+ case hwmon_fan_alarm:
+ break;
+ default:
+ break;
+ }
+ return -EOPNOTSUPP;
+}
+
+static int get_platform(struct ec_sensors_data *data)
+{
+ char system_type[6];
+ int ret = -1;
+ int idx;
+
+ for (idx = 0 ; idx < 6 ; idx++)
+ mutex_lock(&data->mec_mutex);
+ system_type[idx] = get_ec_reg(0xC, (0x10 + idx));
Please avoid unnecessary ( ).
+ mutex_unlock(&data->mec_mutex);
+
+ for (idx = 0 ; idx < 4 ; idx++) {
+ if (strcmp(systems[idx], system_type) == 0) {
Use "!strcmp()".
The length of system_type[] is 6, all fields are written,
and the data is not initialized. There is no guarantee that the
value at string[6] is '\0', and either case strcmp() will read
past the end of the array.
+ ret = idx;
+ break;
+ }
+ }
+ return ret;
+}
+
+static int
+lenovo_ec_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, const char **str)
+{
+ struct ec_sensors_data *state = dev_get_drvdata(dev);
+
+ switch (type) {
+ case hwmon_temp:
+ *str = state->temp_labels[channel];
+ break;
+
+ case hwmon_fan:
+ *str = state->fan_labels[channel];
Some of those strings are empty. Does that mean the fans don't exist ?
If so, don't instantiate them. If it is simply unknown what the fans
do, don't instantiate the attribute either. Returning an empty
string as "label" is not acceptable.
+ break;
+ default:
+ return -EOPNOTSUPP; /* unreachable */
Kind of inconsistent comment. Please drop.
+ }
+ return 0;
+}
+
+static int
+lenovo_ec_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct ec_sensors_data *data = dev_get_drvdata(dev);
+
+ switch (type) {
+ case hwmon_temp:
+ return lenovo_ec_do_read_temp(data, attr, channel, val);
+ case hwmon_fan:
+ return lenovo_ec_do_read_fan(data, attr, channel, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static umode_t
+lenovo_ec_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ switch (type) {
+ case hwmon_temp:
+ if (attr == hwmon_temp_input || attr == hwmon_temp_label)
+ return 0444;
+ break;
+ case hwmon_fan:
+ if (attr == hwmon_fan_input || attr == hwmon_fan_max || attr == hwmon_fan_label)
+ return 0444;
+ break;
+ default:
+ return 0;
+ }
+ return 0;
+}
+
+static const struct hwmon_channel_info *lenovo_ec_hwmon_info[] = {
+ HWMON_CHANNEL_INFO(temp,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL,
+ HWMON_T_INPUT | HWMON_T_LABEL),
+ HWMON_CHANNEL_INFO(fan,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX,
+ HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MAX),
+ NULL
+};
+
+static const struct hwmon_ops lenovo_ec_hwmon_ops = {
+ .is_visible = lenovo_ec_hwmon_is_visible,
+ .read = lenovo_ec_hwmon_read,
+ .read_string = lenovo_ec_hwmon_read_string,
+};
+
+static struct hwmon_chip_info lenovo_ec_chip_info = {
+ .ops = &lenovo_ec_hwmon_ops,
+ .info = lenovo_ec_hwmon_info,
+};
+
+static int lenovo_ec_probe(struct platform_device *pdev)
+{
+ struct device *hwdev;
+ struct ec_sensors_data *ec_data;
+ const struct hwmon_chip_info *chip_info;
+ struct device *dev = &pdev->dev;
+
+ ec_data = devm_kzalloc(dev, sizeof(struct ec_sensors_data), GFP_KERNEL);
+ if (!ec_data)
+ return -ENOMEM;
+
+ dev_set_drvdata(dev, ec_data);
+
+ chip_info = &lenovo_ec_chip_info;
+
+ mutex_lock(&ec_data->mec_mutex);
mutex_init() missing.
+ if (io_read8(MCHP_EMI0_APPLICATION_ID) != 0) { /* check EMI Application BIT */
+ io_write8(0x90C, io_read8(0x90C)); /* set EMI Application BIT to 0 */
+ }
+ io_write8(MCHP_EMI0_EC_ADDRESS_LSB, MCHP_SING_IDX);
+ io_write8(MCHP_EMI0_EC_ADDRESS_MSB, MCHP_SING_IDX >> 8);
This is really unacceptable. It pretty much immediately writes
into i/o registers. I am quite sure this would crash or have
undesirable impact on lots of non-Lenovo systems.
Also, the driver should reserve the register i/o range it uses, not just
use it blindly.
+ mutex_unlock(&ec_data->mec_mutex);
+
+ if ((io_read8(MCHP_EMI0_EC_DATA_BYTE0) == 'M') &&
+ (io_read8(MCHP_EMI0_EC_DATA_BYTE1) == 'C') &&
+ (io_read8(MCHP_EMI0_EC_DATA_BYTE2) == 'H') &&
+ (io_read8(MCHP_EMI0_EC_DATA_BYTE3) == 'P')) {
+ ec_data->platform_id = get_platform(ec_data);
+ switch (ec_data->platform_id) {
+ case 0:
+ ec_data->fan_labels = px_ec_fan_label;
+ ec_data->temp_labels = lenovo_px_ec_temp_label;
+ break;
+ case 1:
+ ec_data->fan_labels = p7_ec_fan_label;
+ ec_data->temp_labels = lenovo_gen_ec_temp_label;
+ break;
+ case 2:
+ ec_data->fan_labels = p5_ec_fan_label;
+ ec_data->temp_labels = lenovo_gen_ec_temp_label;
+ break;
+ case 3:
+ ec_data->fan_labels = p7_amd_ec_fan_label;
+ ec_data->temp_labels = lenovo_gen_ec_temp_label;
There is only a single set of temperature labels. ec_data->temp_labels
is therefore unnecessary and lenovo_gen_ec_temp_label can be used directly.
+ break;
+ default:
+ dev_err(dev, "Unknown ThinkStation Model");
Maybe better "Unsupported"
+ return -EINVAL;
-ENODEV;
+ }
+
+ hwdev = devm_hwmon_device_register_with_info(dev, "lenovo_ec",
+ ec_data,
+ chip_info, NULL);
+
+ return PTR_ERR_OR_ZERO(hwdev);
+ }
+ return -ENODEV;
Error handling should come first.
+}
+
+static struct platform_driver lenovo_ec_sensors_platform_driver = {
+ .driver = {
+ .name = "lenovo-ec-sensors",
+ },
+ .probe = lenovo_ec_probe,
+};
+
+static struct platform_device *lenovo_ec_sensors_platform_device;
+
+static int __init lenovo_ec_init(void)
+{
+ lenovo_ec_sensors_platform_device =
+ platform_create_bundle(&lenovo_ec_sensors_platform_driver,
+ lenovo_ec_probe, NULL, 0, NULL, 0);
+
+ if (IS_ERR(lenovo_ec_sensors_platform_device))
+ return PTR_ERR(lenovo_ec_sensors_platform_device);
+
+ return 0;
+}
Isn't there a means to determine if this is a supported Lenovo system
prior to calling the probe function ? DMI data, maybe ?
+
+static void __exit lenovo_ec_exit(void)
+{
+ platform_device_unregister(lenovo_ec_sensors_platform_device);
+ platform_driver_unregister(&lenovo_ec_sensors_platform_driver);
+}
+
+module_init(lenovo_ec_init);
+module_exit(lenovo_ec_exit);
+
+MODULE_AUTHOR("David Ober <dober@xxxxxxxxxx>");
+MODULE_DESCRIPTION("HWMON driver for MEC172x EC sensors on LENOVO motherboards");
+MODULE_LICENSE("GPL");
